The purpose of the Core is to provide two key scientific support services for members of the Program. First is to grow and maintain leukemic myeloid cell lines and other cells for the Program members at Cold Spring Harbor Laboratory. Second is to provide synthetic peptides to all members of the Program. Cultured cells are the basis for nearly all f the basic research questions in projects that are to be performed at Cold Spring Harbor Laboratory. The cell culture model system for much of the work is the Mo7 cell line, and a variant, known as Mo7/p210, that stably expresses p210bcr/abl. These cells will be used for studies of the tyrosine kinase substrate, pp62; phosphorylation of p210bcr/abl; protein kinases; and protein tyrosine phosphatases. Large number of these cells will be needed to accomplish the stated aims of these projects. In addition to the Mo7 and Mo7/p210 cells, the Core will maintain several other lines for alternatives to Mo7 experiments and other functional experiments on p210bcr/abl. These lines include K562 and RW-Leu4, which both express high levels of p210bcr/abl, as well as NIH3T3 cells for testing the transforming ability of mutant p210bcr/abl constructs. New cell lines developed as stable derivatives of Mo7 or other parent lines will be maintained by the Core and distributed to all members of the Program as a research tool. Peptides will be prepared by chemical synthesis on solid phase supports using automated equipment. The uses of the peptides include: (i) peptides to the junction regions of p210bcr/abl and p185bcr/abl, for production of specific antisera; (ii) phosphopeptides based on phosphorylation sites on p210bcr/abl; (iii) peptide substrates for the PTP-1B associated kinase, (e.g. based on retinoblastoma); (iv) peptides from the PTP-1B associated kinase sequence for production of specific antibodies; (v) additional quantities of peptides to compete existing anti-peptide sera in control experiments, such as immunoprecipitations and immunofluorescence; (vi) additional quantities of existing synthetic peptide substrates for protein kinases and phosphatases; (vii) peptide antigens based on sequences of potential p210bcr/abl substrates, such as p62. The Core leader will design each peptide and assure that the synthetic product is chemically homogeneous.